C<binmode>, C<close>, C<closedir>, C<dbmclose>, C<dbmopen>, C<die>, C<eof>,
C<fileno>, C<flock>, C<format>, C<getc>, C<print>, C<printf>, C<read>,
-C<readdir>, C<rewinddir>, C<seek>, C<seekdir>, C<select>, C<syscall>,
+C<readdir>, C<rewinddir>, C<say>, C<seek>, C<seekdir>, C<select>, C<syscall>,
C<sysread>, C<sysseek>, C<syswrite>, C<tell>, C<telldir>, C<truncate>,
C<warn>, C<write>
C<caller>, C<continue>, C<die>, C<do>, C<dump>, C<eval>, C<exit>,
C<goto>, C<last>, C<next>, C<redo>, C<return>, C<sub>, C<wantarray>
+=item Keywords related to switch
+
+C<break>, C<continue>
+
+(These are only available if you enable the "switch" feature.
+See L<feature> and L<perlsyn/"Switch statements">.)
+
=item Keywords related to scoping
C<caller>, C<import>, C<local>, C<my>, C<our>, C<package>, C<use>
See L<perlmod/"Perl Modules">.
+=item break
+
+Break out of a C<given()> block.
+
+This keyword is enabled by the "switch" feature: see L<feature>
+for more information.
+
=item caller EXPR
X<caller> X<call stack> X<stack> X<stack trace>
=item continue BLOCK
X<continue>
+=item continue
+
C<continue> is actually a flow control statement rather than a function. If
there is a C<continue> BLOCK attached to a BLOCK (typically in a C<while> or
C<foreach>), it is always executed just before the conditional is about to
empty one, logically enough. In that case, C<next> goes directly back
to check the condition at the top of the loop.
+If the "switch" feature is enabled, C<continue> is also a
+function that will break out of the current C<when> or C<default>
+block, and fall through to the next case. See L<feature> and
+L<perlsyn/"Switch statements"> for more information.
+
+
=item cos EXPR
X<cos> X<cosine> X<acos> X<arccosine>
=item gmtime
-Converts a time as returned by the time function to an 8-element list
+Converts a time as returned by the time function to an 9-element list
with the time localized for the standard Greenwich time zone.
Typically used as follows:
- # 0 1 2 3 4 5 6 7
- ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday) =
+ # 0 1 2 3 4 5 6 7 8
+ ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
gmtime(time);
All list elements are numeric, and come straight out of the C `struct
indicating December. $year is the number of years since 1900. That
is, $year is C<123> in year 2023. $wday is the day of the week, with
0 indicating Sunday and 3 indicating Wednesday. $yday is the day of
-the year, in the range C<0..364> (or C<0..365> in leap years.)
+the year, in the range C<0..364> (or C<0..365> in leap years). $isdst
+is always C<0>.
Note that the $year element is I<not> simply the last two digits of
the year. If you assume it is then you create non-Y2K-compliant
Implements the ioctl(2) function. You'll probably first have to say
- require "sys/ioctl.ph"; # probably in $Config{archlib}/ioctl.ph
+ require "sys/ioctl.ph"; # probably in $Config{archlib}/sys/ioctl.ph
to get the correct function definitions. If F<sys/ioctl.ph> doesn't
exist or doesn't have the correct definitions you'll have to roll your
=item rindex STR,SUBSTR
-Works just like index() except that it returns the position of the LAST
+Works just like index() except that it returns the position of the I<last>
occurrence of SUBSTR in STR. If POSITION is specified, returns the
-last occurrence at or before that position.
+last occurrence beginning at or before that position.
=item rmdir FILENAME
X<rmdir> X<rd> X<directory, remove>
The substitution operator. See L<perlop>.
+=item say FILEHANDLE LIST
+X<say>
+
+=item say LIST
+
+=item say
+
+Just like C<print>, but implicitly appends a newline.
+C<say LIST> is simply an abbreviation for C<print LIST, "\n">,
+and C<say()> works just like C<print($_, "\n")>.
+
+That means that a call to say() appends any output record separator
+I<after> the added newline.
+
+This keyword is only available when the "say" feature is
+enabled: see L<feature>.
+
=item scalar EXPR
X<scalar> X<context>
X<setsockopt>
Sets the socket option requested. Returns undefined if there is an
-error. OPTVAL may be specified as C<undef> if you don't want to pass an
-argument.
+error. Use integer constants provided by the C<Socket> module for
+LEVEL and OPNAME. Values for LEVEL can also be obtained from
+getprotobyname. OPTVAL might either be a packed string or an integer.
+An integer OPTVAL is shorthand for pack("i", OPTVAL).
+
+An example disabling the Nagle's algorithm for a socket:
+
+ use Socket qw(IPPROTO_TCP TCP_NODELAY);
+ setsockopt($socket, IPPROTO_TCP, TCP_NODELAY, 1);
=item shift ARRAY
X<shift>
in the latter case, it is usually counter-productive to declare $a and
$b as lexicals.
-In either case, the subroutine may not be recursive. The values to be
-compared are always passed by reference and should not be modified.
+The values to be compared are always passed by reference and should not
+be modified.
You also cannot exit out of the sort block or subroutine using any of the
loop control operators described in L<perlsyn> or with C<goto>.
=item vector flag
-The vector flag C<v>, optionally specifying the join string to use.
-This flag tells perl to interpret the supplied string as a vector
-of integers, one for each character in the string, separated by
-a given string (a dot C<.> by default). This can be useful for
-displaying ordinal values of characters in arbitrary strings:
+This flag tells perl to interpret the supplied string as a vector of
+integers, one for each character in the string. Perl applies the format to
+each integer in turn, then joins the resulting strings with a separator (a
+dot C<.> by default). This can be useful for displaying ordinal values of
+characters in arbitrary strings:
+ printf "%vd", "AB\x{100}"; # prints "65.66.256"
printf "version is v%vd\n", $^V; # Perl's version
Put an asterisk C<*> before the C<v> to override the string to
described when they are both C<undef>. This case will also trigger an
uninitialized warning.
+On systems that support futimes, you might pass file handles among the
+files. On systems that don't support futimes, passing file handles
+produces a fatal error at run time.
+
=item values HASH
X<values>
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